Enhanced admission control in relay-enhanced access networks

1. A method comprising

receiving a bearer admission request of at least one bearer at one of a relay node and a base station in a relay-enhanced access network, said at least one bearer consisting of a bearer on an access link between a user equipment and said relay node and a bearer on a backhaul link between said relay node and said base station,

executing a bearer admission control of said at least one bearer on a first link of said at least one bearer at the one of said relay node and said base station,

identifying a set of bearers among said at least one bearer, which are admitted on said first link as a result of said execution of said bearer admission control at the one of said relay node and said base station, and

based on the identifying, determining that said identified set of bearers can be supported by a second link of said at least one bearer and transmitting a modified bearer admission request of said identified set of bearers for execution of a bearer admission control on the second link of said at least one bearer to the one of said relay node and said base station when at least one bearer is identified to be admitted on said first link, else

if it is determined that said identified set of bearers are not supported by the second link, transmitting a bearer admission request acknowledgment indicating rejection of the bearer admission request of said at least one bearer.

2. The method according to claim 1 , upon transmitting said modified bearer admission request, further comprising

receiving a bearer admission request acknowledgment from the one of said relay node and said base station, including information on bearers among said identified set of bearers, which are admitted on said second link as a result of the execution of said bearer admission control at the one of said relay node and said base station, and

transmitting a bearer admission request acknowledgment indicating admission of bearers on both said first and second links in accordance with said information on bearers.

3. The method according to claim 1 , wherein said method is operated at said relay node, said first link comprises said access link and said second link comprises said backhaul link.

4. The method according to claim 3 , wherein said bearer admission request acknowledgment indicating rejection of the bearer admission request of said at least one bearer is transmitted to the base station.

5. The method according to claim 1 , wherein said method is operated at said base station, said first link comprises said backhaul link and said second link comprises said access link.

6. The method according to claim 5 , wherein said bearer admission request acknowledgment indicating rejection of the bearer admission request of said at least one bearer is transmitted to another base station from which a handover of the user equipment is to be performed.

7. The method according to claim 1 , said bearer admission control comprising

obtaining information on available resources on said first link, and

checking whether sufficient access link resources for admitting said at least one bearer on said first link are available or are to be made available by at least one of dropping one or more existing bearers on said first link having a lower priority than at least one bearer requested for admission and by dropping one or more existing bearers on said second link having a lower priority than at least one bearer requested for admission.

8. The method according to claim 1 , wherein, when a bearer admission for more than one bearer is requested,

said method further comprises at least one of

prioritizing the bearers requested for admission and executing the bearer admission control on said first link in the order of prioritization of the bearers, and

the bearer admission control on said first link for the bearers requested for admission is executed either in a successive manner for one bearer at a time or in a joint manner for more than one or all of the bearers at a time.

9. The method according to claim 1 , wherein said bearer admission request comprises or is comprised in at least one of a handover request, a bearer setup request and a bearer modification request.

10. The method according to claim 1 , wherein the bearer admission request is a handover request and wherein identifying a set of bearers further comprises identifying a list of backhaul-admitted bearers that are bearers remaining after bearers which cannot be admitted in the backhaul are removed from an original list of bearers in the handover request, and wherein transmitting further comprises sending a modified handover request including the list of backhaul-admitted bearers to said relay node.

11. The method according to claim 1 , wherein the determining that said identified set of bearers can be supported by the second link comprises determining one of that a guaranteed bit rate of said identified set of bearers is supported by the second link, and that said identified set of bearers is not associated with a guaranteed bit rate.

12. An apparatus comprising

at least one processor; and

at least one memory including computer program code, where the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to at least:

receive a bearer admission request of at least one bearer at one of a relay node and a base station in a relay-enhanced access network, said at least one bearer consisting of a bearer on an access link between a user equipment and said relay node and a bearer on a backhaul link between said relay node and said base station,

execute a bearer admission control of said at least one bearer on a first link of said at least one bearer at the one of said relay node and said base station, and to identify a set of bearers among said at least one bearer, which are admitted on said first link as a result of said execution of said bearer admission control at the one of said relay node and said base station,

based on the identifying, determine that said identified set of bearers can be supported by a second link of said at least one bearer and transmit a modified bearer admission request of said identified set of bearers for execution of a bearer admission control on the second link of said at least one bearer to the one of said relay node and said base station when at least one bearer is identified to be admitted on said first link, else

if it is determined that said identified set of bearers are not supported by the second link, transmit a bearer admission request acknowledgment indicating rejection of the bearer admission request of said at least one bearer.

13. The apparatus according to claim 12 , wherein the at least one memory including the computer program code is configured with the at least one processor to cause the apparatus, upon transmitting said modified bearer admission request, to:

said receiver is configured to receive a bearer admission request acknowledgment from the one of said relay node and said base station, including information on bearers among said identified set of bearers, which are admitted on said second link as a result of the execution of said bearer admission control at the one of said relay node and said base station, and

said transmitter is configured to transmit a bearer admission request acknowledgment indicating admission of bearers on both said first and second links in accordance with said information on bearers.

14. The apparatus according to claim 12 , wherein said apparatus is operable at said relay node, said first link comprises said access link and said second link comprises said backhaul link.

15. The apparatus according to claim 14 , wherein the at least one memory including the computer program code is configured with the at least one processor to cause the apparatus to transmit said bearer admission request acknowledgment indicating rejection of the bearer admission request of said at least one bearer to the base station.

16. The apparatus according to claim 12 , wherein said apparatus is operable at said base station, said first link comprises said backhaul link and said second link comprises said access link.

17. The apparatus according to claim 16 , wherein the at least one memory including the computer program code is configured with the at least one processor to cause the apparatus to transmit said bearer admission request acknowledgment indicating rejection of the bearer admission request of said at least one bearer to another base station from which a handover of the user equipment is to be performed.

18. The apparatus according to claim 12 , wherein the at least one memory including the computer program code is configured with the at least one processor to cause the apparatus to

obtain information on available resources on said first link, and

check whether sufficient access link resources for admitting said at least one bearer on said first link are available or are to be made available by at least one of dropping one or more existing bearers on said first link having a lower priority than at least one bearer requested for admission and by dropping one or more existing bearers on said second link having a lower priority than at least one bearer requested for admission.

19. The apparatus according to claim 12 , wherein the at least one memory including the computer program code is configured with the at least one processor to cause the apparatus to, when a bearer admission for more than one bearer is requested, at least one of

prioritize the bearers requested for admission and execute the bearer admission control on said first link in the order of prioritization of the bearers, and

execute the bearer admission control on said first link for the bearers requested for admission either in a successive manner for one bearer at a time or in a joint manner for more than one or all of the bearers at a time.

20. The apparatus according to claim 12 , wherein said bearer admission request comprises or is comprised in at least one of a handover request, a bearer setup request and a bearer modification request.

21. The apparatus according to claim 12 , wherein the bearer admission request is a handover request and wherein the bearer admission control processor is further configured to identify a set of bearers further comprises identifying a list of backhaul-admitted bearers that are bearers remaining after bearers which cannot be admitted in the backhaul are removed from an original list of bearers in the handover request, and wherein the at least one memory including the computer program code is configured with the at least one processor to cause the apparatus to send a modified handover request including the list of backhaul-admitted bearers to said relay node.

22. A non-transitory computer-readable storage medium on which software code portions are embodied for use with a processor, the software code portions executed by the processor to perform operations comprising:

receiving a bearer admission request of at least one bearer at one of a relay node and a base station in a relay-enhanced access network, said at least one bearer consisting of a bearer on an access link between a user equipment and said relay node and a bearer on a backhaul link between said relay node and said base station,

executing a bearer admission control of said at least one bearer on a first link of said at least one bearer at the one of said relay node and said base station,

identifying a set of bearers among said at least one bearer, which are admitted on said first link as a result of said execution of said bearer admission control at the one of said relay node and said base station,

based on the identifying, determining that said identified set of bearers can be supported by a second link of said at least one bearer and transmitting a modified bearer admission request of said identified set of bearers for execution of a bearer admission control on the second link of said at least one bearer to the one of said relay node and said base station when at least one bearer is identified to be admitted on said first link, else

if it is determined that said identified set of bearers are not supported by the second link, transmitting a bearer admission request acknowledgment indicating rejection of the bearer admission request of said at least one bearer.

23. The non-transitory computer-readable storage medium according to claim 22 , wherein the bearer admission request is a handover request and wherein identifying a set of bearers further comprises identifying a list of backhaul-admitted bearers that are bearers remaining after bearers which cannot be admitted in the backhaul are removed from an original list of bearers in the handover request, and wherein transmitting further comprises sending a modified handover request including the list of backhaul-admitted bearers to said relay node.